Differential axle for railroad cars



Patented Oct. 4, 1927.

JaMnsB. "POPE, or sanI rnANcIsco, CALIFORNIA.'

DIEFERENTIAL AXLn Fon 'RAILROAD cans.

Application nled August 9, 19,26. SerialNa 128,127.

This invention relates to railwayk rolling stock and particularlypertains to differential axles 'for railway cars.

It is Acommon practice in the operation and maintenance of railway carsto provide car axles having a Qflangecl track wheel rigidly secu-red ateach 'endlof the axle. Such a construction, however, contributes 'to therapid wear-ing of 'the rails, journals, trucks and wheels of the cars,as well vas often pros duces broken wheels and broken :or `sprung axles.

Another marked detriment caused bythe use of a rigid axfleto which thewheels are fixed is that dueto variable friction -upon the two rails ofthe track and excessive resistance offered when the Wheels of an axle.are travelling on a. curved track, a considerable amount of theldriving torce of thelengine is dissipated, Athis being caused Aby thenecessity :for slippage =between1the wheels andthe lrails as they areforced to travel along vdifferent lineal distances While rotating invunison.

It is the principal Jobject of the present invention, therefore, toprovide means for permitting differential operation of the two wheelscarried by a railroad axle :so that the two Wheels of each axle willreadily adapt themselves to varyingxroad conditions, slippage andfriction coeliieients, thereby `decreasing sho'ck upon all of ltheparts-iin preventing wear of the rails and wheels.

The present invention icontemplates `the use of an laxle formed in ltwolongitudinally r aligned sections, the louter ends oi' each -section,being -ittecl with aa wheel and the contiguous ends :of the sectionsfbeiIn-g held to-` gether a manner to prevent relative longitudinalmovement while permitting inde` pendent rotation.

The invention is illustrated 'by way -o -example in the accompanyingdrawing, in which-4 Fig. 1 is a view insection and elevation showing thetruck of a railway -car tand more particularly disclosing the.diderential axle. v f

Fig. 2is .an enlarged view in perspective showing one-half of thedifferential coupling sleeve and further indicating a part or' Yoneaxle-section in solid lines and another par-tof said section in dottedlines.

Fig.l 3 is an enlarged transverse section through the differential :axleas seen lon the line ii-'3 of Figure 1. l

TF ig. 4l is 1an enlarged view in perspective showing one ofthedifferential sleeve pins.

Referring more #particularly-to the ldrawving: 10 indicates arailway carmounted upon sui-table -girde-rs 411, which are in 'turn lcarried by thecross Vbeams 12. These beams Iare designed to rest upon suitable springsus pension members 125, carried by truck frames 14. Journal boxes alsoform a part of the ltruck l'raines let andare adapted to reoeive theouter' proj ec-ting lends of an `axle This axle carries flanged railwheels-17 and 18. In the present instance,the rail Wheels areindependent of ea-ch other, #due to the tact that the axle 16' isvformed in sections 19 and 20, upon which the wheels 17' and v18 aremounted respectively. and 200i thefaxle 16 are held in vlongitmlinalalignment and are vpemnittedto have inde# pendent rotation around theirlongitudinal axis ydue to the provision l'of a dinerential The sections19 f coupling sleeve'2`1. rlhis sleeve is formed in' fr two'semi-'circular halves 22'and'23, as' more clearly shown in Fig. -3 Iofthe drawing. Complementary interlocking lugs 424E yare formed upondia-metrically -oppositelsides lor thesleeve ysections 22 and '25, `andextend above; and .below the *parting line lor the sleeves. 'Byreference lto Figure 2 oi the drawing, it will Ibe seenthat these lugsare uniform-ly spaced with relation to yeach other zlong the oppositesides ot the sleeve niem- 61.5 c

reference to Figure 1, it will `be see-n that the lugs of one-haltet thesleeve are staggered with relation to the other half or' the. sleeve sothat they :become complementary and interlock; T-hismakes it possible tosecurely lasten the two-'halvesot-thel cliiiferentialecoupling sleevetogether by two pins 25,- Which extend p a'ral-lelto the longitudinalaxis of the sleeve and project through a gradual-ly tapering openingformed through 'the series of yinte'rloclred *lugs 24 along 'oppositesides oil the sleeve. By driving the tapered pins through the openings26, i-t is possible toA firmly hold the two halvesof the dilferentialcoupling sleeve together without causing the halves to variably andobjectionably'grip the axle sections 19 and 2O whenthe sleeve is inposition thereon. Cotter pinsQ? are provided to be driven through thesmaller ends of the pins to prevent `the sleeve pins. from acci'-dental-ly' loosen-ing and working their way out of the sleeve. Theassembled differential coupling sleeve 21'is formed With'a y 4 ylongitudinally extending cent-ral bore 28, which substantially agreeswith the outside diameter of the axle sections 19 and 20. Formed atequal spaced intervals along the face of the bore 28 are shoulders 29which have a circula-r face described by a circle of smaller diameterthan the diameter of the axle, but concentric thereto. The shouldersthus spaced provide intermediate grooves 30 of substantially the samewidth as the shoulders. It will also be noted, by reference to Figure 2,that the lugs 24 for the most part occur opposite the groove section andact to reinforce the same, while the shoulders occur in the relativelyweaker points between the lugs and act to reinforce the wall of thedifferential sleeve. By this design and arrangement it is possible tosecure a strong` coupling sleeve for the pui'- pose intended but by theuse of a minimum amount of metal.

The cylindrical face of the contiguous ends of the axle sections 19 and2U are formed with grooves 31 of a width and depth to properly` receivethe shoulders 29 of the coupling sleeve when the shoulders are fittedtherein and the halves of the coupling sleeve are secured together bythe pins 25. rlhis means makes it possible for the axle sections 19 and20 to have independent rotation with relation to each other andthedifferential sleeve, while the sections will be securely coupledagainstrrelative longitudinal movement. Y A

In the operation and use, of the present invention, it will beunderstood that the differential coupling sleeve may be applied to theaxles of cars in userat the present time, or to the axles of cars duringthe course of manufacture. In either event it has been found desirableto suitably lcut the grooves 31 in the outer face of the axle 16. Afterthis has been done the axle may be cut in two at the point indicated bythe numeral 32 'in Fig. 2 of the drawing to form axle sections 19 and20. It will be understood, however, that the grooves 31 have beenmachined in a manner to cause them to accommodate the shoulders 29formed within `.the differential coupling sleeve 22, and that before theaxle is cut in two care is taken to insure that the grooves andshoulders on the axle and within the differential coupling sleeve willbe `complementary to permit the assembled sleeve to embrace the axlewith a free running fit, while preventing longitudinal shifting movementof the sleeve along the axle.

After the axle 16 has been cut in two to form the sections 19 and 20,the ends of the sections are planed smooth and a wear disc 33 agreeingin diameter with the diameter of the axle and in thickness with the cutformed through the axle, is interposed between the contiguous ends ofthe axle sections. rlhe two halves of the differential coupling sleevemay then be secured in position with relation to each other and the axlesections by driving the pins through the series of lugs interlockingalong opposite sides of the differential sleeve and thereafter securingthe taper pins by the use of cotter pins27, the taper openings taperingin opposite directions if desired.

lt will thus be seenthat by the construction here disclosed, independentdifferenf tial movement of the two wheels of a car axle may be free totake place, due to the provision and use of a simple differentialcoupling structure whichis of suliicient strength to maintain theoriginal .strength of the axle and to kwithstand the shock, strain andstresses to which the axle is subjectod, said structure being decidedlysimple in its construction, the mannerl of assembling, and inexpensiveboth as to initial cost and installation.

l/Vhile l have shown the preferred form* of my invention as new known toine,rit

will be understood that various changes may be made in the combination,construction and arrangement of parts by those skilled in the artwithout departing from 'the spirit of the invention as claimed.

y Alaving thus described my invention, what claim and desire/tol secureby Letters Patent is-- p Y 1. A differential axle for railroad cars,comprising a 'two-part axle, a wheel fixed on the outer end ofeacli`.axle part, atwo-part sleeve adapted to embrace contiguous ends ofthe axle sectionsand to holdthem in longitudinal alignment with eachother wliilepermitting relatively free rotation of the axle parts withinthe sleeve, said sleeve parts being formed along opposite halves withcomplementary interlocking lugs through which progressively taperedopenings occur, tapered -pins adapted to be driven through the openingsin said lugs to rigidly hold the halves of the sleeve in yfixedrelationy to each other and the axle, and

. means within the sleeve to prevent longitudinal movement of the sleeveon the axle parts. l

2. A dilferentia-l axlev for railroad cars, comprising a two-part axle.a wheel fixed on the outer end of each axle part, a two-part sleeveadapted to` embrace contiguousends of the axle sections andfto holdlthem in longitudinal alignment with each` other while permittingrelatively free rotation of the axle parts within the sleeve, vsaidsleeve parts being formed along opposite halves with complementarythrough which progressively` tapered openings oceur, taperedr pinsadapted to be driven through the openings in said lugs to interlockinglugs'` 1'2'5 exclusively and rigidly hold the4 halves of the sleeve infixed relation to eachother and the axle, andl means witliinthesleeve toprevent longitudinal movement of 8. A dierential axle for railroad cars,

comprising a two-part axle, a Wheel fixed on the outer end of each axlepart, a twopari; sleeve adapted to embrace contiguous ends of the axlesections to hold them in longitudinal alignment With each other Whilepermitting relative reerotation of the axle parts Within the sleeve,said sleeve being formed along opposite edges with complementaryinterlocking lugs having openings which register when the parts vof thesleeve are in their assembled positions, and members passing through thelugs and parallel to the axis of the axles for holding said sleeve partsin fixed relation other upon the axles.

il. A differential axle for railroad cars, comprising a two-part axle, awheel fixed on the outer end of each axle part, the contiguous portionsof the axles being formed With a plurality of spaced circumferentialgrooves on their cylindrical surfaces, a tWopart sleeve adapted toembrace the contiguous ends of said axles, said sleeve being formed Withshoulders to fit Within the circumferential extending grooves on thecylindrical face of the axle parts, a plurality of interlocking lugsformed along opposite complementary edges of the sleeves, said to eachlugs having registering openings and members extending through saidopenings and parallel to the axle for 'rigidly holding the sleevesections in fixed relation to each other and inl their fitted positionupon the axle parts.

5. A differential axle for railroad cars, comprising a two-part axle, awheel fixed on the outer end of each axle part, the contiguous portionsof the axles being formed With-a plurality of spaced circumferentialgrooves on their cylindrical surfaces, a tvvo-y part sleeve adapted toembrace the contiguous end of said axles, said sleeve being formed withshoulders to fit Within the circumferential extending grooves on thecylindrical face of the axle parts, a plurality of interlocking lugsformed along opposite complementary edges of the sleeves, said lugshaving registering openings and members extending through said openingsand parallel to the axle for rigidly holding the sleeve sections infixed relation to each other and in their fitted position upon the axleparts, said registering openings in the lugs forming a substantiallycontinuous tapered opening throughout the length of the sleeve and thefastening members passing therethrough being also tapered.

JAMES B. POPE.

